Evaluating Root Cause Analysis Options: Change Analysis
Change Analysis Features:
I have not seen change analysis called out as a tool for finding root causes by itself. The KT ‘is/ is not’ problem solving tool is the closest thing to change analysis that I have seen. As I stated above, this KT tool is in essence the same as the TapRooT® Change Analysis tool.
Change Analysis Advantages:
It is always useful to compare what should have happened to what did happen when analyzing a problem. This effort alone however will rarely lead you the root causes of, and corrective actions for, preventing the problem in the future.
Change Analysis Disadvantages:
The Change Analysis tool compares what should have happened to what did happen. Comparisons are made across the ‘who, what, when, where, and how’ question dimension to collect information. In turn, use of this tool may not lead you to the actual root causes and corrective actions to prevent problem return.
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Evaluating Root Cause Analysis Options: Fishbone or Ishikawa Diagram
This tool is perhaps the oldest, and most well known, root cause analysis tool. In its most common form of use, the user attempts to define multiple possible causes for a given problem. Possible causes could come from four different areas – manpower, methods, materials, and machines. Teams often use the ‘5 Whys’ technique with this tool to help construct the bones of the chart. The answer to each ‘why’ question results in a new branch off of the previous one that the question originated from.
This tool builds on simple list creation. The fishbone diagram serves as a useful tool to capture individual opinions. The team can talk about the information in-hand and identify additional possible causes. In a lot of ways, it is similar to identifying the conditions for a Snapchart, but that is where the comparison ends.
The fishbone diagram is an opinion-based tool. Its design limits the user’s ability to visually define multiple levels of ‘why’ answers, unless the visual medium in use is really large. Worse yet, users rely on opinion (a vote of some form) to select the most likely causes from the list. Teams then define and test possible countermeasures for the selected causes to see if the problem goes away. This can consume significant time and money. The tool also does not focus on generic cause identification and and elimination.